Leakage of inflammable, explosive or toxic gasses and liquids is a major threat to human lives and properties. If unnoticed and not stopped and dealt with on time, It may result in ignition, explosion or inhalation of these dangerous substances, and subsequently in heavy casualties and damages.
Various leakage detectors are known both for industrial and home use. For example, many buildings are equipped with smoke detectors which detect the presence of smoke produced by flames and produce an alarm signal or activate water sprinklers to put out the fire. Gas detectors are also known, and widely used.
Simple types of detectors merely detect the presence of dangerous substances, whereas more sophisticated devices incorporate detection and activation of other systems generally aimed at preventing further leakage and/or removing or neutralizing the danger imposed by those leaked substances.
In EP 440828 (Gazzaz) a gas monitoring system with leak detection and flow cut off was disclosed for controlling the flow of gas from a pressurized gas container to a cooking range of a kitchen. Leaked gas is detected by a sensor which activates a visual and an audible alarm and which operates said valve to terminate the gas flow. It comprised a valve having a solenoid having an energized position for retaining the valve in an open position allowing gas to flow through the valve and a deenergized position in which the valve is shut off.
In EP 523655 (Feleppa), a safety device for detecting gas leaks was described, comprising a gas detection electronic circuit, which signals electro-magnetic waves with radio frequency, at the event of gas leak detection, to a second electronic circuit, and controls a solenoid valve for the opening and closing of the gas supply in said gas system.
UK Pat. Application publication no. 2159249 (Fuentetaja) it was disclosed a shut-off valve for the automatic closure of a gas supply, comprising a body, having an angled passage corresponding to the gas inlet, having a valve head or obturator which is urged towards an associated seat by a spring. A locking pin whose distal end is positioned inside a groove on a stem extending from the valve head, locks the valve-head in an open position. Upon the detection of a gas leak the locking pin is drawn out of the groove, by means of an electromagnet actuating the removal of the locking pin from the groove.
The abovementioned inventions seem like good solutions for the prevention of gas leaks in gas systems. But require a major adjustment to be carried out on existing gas systems, as the introduction of a new component (i.e. the automatic valve) into the existing system, and its installation is necessary. Moreover, the installation of such devices in existing gas systems require the employment of skilled specialist workers, and cannot be done by an ordinary person, who generally is the user of such gas systems.